Benthic Resources Assessment Technique Evaluation of Potential Dredged Material Disposal Sites in Puget Sound. Phase 2 Sites.

摘要

The U.S. Army Engineer District, Seattle is currently involved in a decision making process regarding the designation of open water dredged material disposal sites in Puget Sound and adjacent waters. In 1985 a joint effort was initiated to examine long term requirements and strategies for open-water disposal of dredged materials. The quality of benthic habitats at proposed disposal sites was identified as a major topic of interest in the PSDDA study because of potential impacts to demersal fish feeding habitat. One aspect of benthic habitat quality is the relative amount of trophic support that a given benthic habitat provides demersal bottom-feeding fishes. analytical procedures have been developed to estimate this aspect of benthic habitat quality. These procedures are collectively called the Benthic Resources Assessment Technique, or BRAT. The BRAT analysis involves the collection of two data sets; one which describes benthic biomass in terms of size and vertical distribution in sediments at selected sites, and a second which describes the foraging depth and prey size exploitation pattern of demersal fishes at those sites. The BRAT then estimates that portion of the total benthic infaunal biomass that is both available and vulnerable to predation by target fishes. (KT)